Carbon catalyst, battery electrode, and battery

Abstract

A carbon catalyst, a battery electrode, and a battery, each exhibits excellent catalytic performance. A carbon catalyst contains two kinds of transition metals and has such a carbon structure that an interplanar spacing d002, which is determined from a Bragg angle of one of three diffraction peaks fbroad, fmiddle, and fnarrow obtained by separating a diffraction peak around a diffraction angle (2θ) of 26° in an X-ray diffraction pattern of powder X-ray diffraction with a CuKα ray, the one diffraction peak being the diffraction peak fbroad, is 0.374 nm or more.

The invention claimed is: 
     
       1. A carbon catalyst, comprising:
 two kinds of transition metals; and 
 a carbon structure having an interplanar spacing d 002  of 0.374 nm or more, the interplanar spacing d 002  being determined from a Bragg angle of a diffraction peak f broad  which is one of three diffraction peaks f brothreead , f middle , and f narrow  obtained by separating a diffraction peak around a diffraction angle (2θ) of 26° in an X-ray diffraction pattern of the carbon structure by powder X-ray diffraction with a CuKα ray, wherein: 
 the diffraction peak f broad  has a diffraction angle (2θ) of 24.0°±4.0°, 
 the diffraction peak f middle  has a diffraction angle (2θ) of 26.2°±0.3°, and 
 the diffraction f narrow  peak has a diffraction angle (2θ) of 26.5°±0.5°. 
 
     
     
       2. The carbon catalyst according to  claim 1 , wherein the carbon structure has a crystallite size Lc of 1.19 nm or more and 2.17 nm or less, the crystallite size Lc being determined from the Bragg angle of the diffraction peak f broad . 
     
     
       3. The carbon catalyst according to  claim 1 , wherein the carbon structure has a crystallite size La of 2.39 nm or more and 2.89 nm or less, the crystallite size La being determined from a Bragg angle of a carbon (100) diffraction line f 100  obtained by separating a diffraction peak around a diffraction angle (2θ) of 45° in the X-ray diffraction pattern of powder X-ray diffraction with a CuKα ray. 
     
     
       4. The carbon catalyst according to  claim 1 , wherein the carbon structure has an average carbon network plane size L of 10 nm or more and 40 nm or less, the average carbon network plane size L being determined by temperature-programmed desorption analysis allowing a temperature increase up to 1,600° C. 
     
     
       5. The carbon catalyst according to  claim 1 , wherein the carbon catalyst exhibits a voltage E O2  of 0.820 V (vs. NHE) or more at a reduction current of −10 μA/cm 2  in an oxygen reduction voltammogram obtained by sweeping potential using a rotating disc electrode apparatus having a working electrode containing the carbon catalyst. 
     
     
       6. The carbon catalyst according to  claim 1 , wherein the carbon catalyst exhibits an absolute value of a current density i 0.7  (mA/cm 2 ) of 0.92 or more at a voltage of 0.7 V (vs. NHE) in an oxygen reduction voltammogram obtained by sweeping potential using a rotating disc electrode apparatus having a working electrode containing the carbon catalyst. 
     
     
       7. The carbon catalyst according to  claim 1 , wherein the carbon catalyst comprises, as the two kinds of transition metals, two kinds of transition metals selected from a group consisting of scandium, titanium, vanadium, chromium, manganese, iron, cobalt, nickel, copper, and zinc. 
     
     
       8. A battery electrode, comprising the carbon catalyst of  claim 1 . 
     
     
       9. A battery, comprising the battery electrode of  claim 8 .